Navigation NAU 102 Lesson 4

Projection Comparisons

Other Projections Stereographic/Orthographic Used for polar navigation and decoration Points projected from opposite side of the earth or from infinity

Plotting Sheets Used mid-ocean Pre-labeled latitude lines No land/ocean features Unlabeled longitude lines You can make your own!

Plotting Sheets Universal Plotting Sheet You label the latitude lines Can be used for any latitude/longitude You draw the longitude lines Longitude scale varies by mid-latitude

Chart Scales Scale – the ratio of a given distance on the chart to the actual distance which it represents on Earth. e.g. 1:80,000 or 1/80,000 1 inch on chart = 80,000 inches on Earth

Chart Scales Scale can be stated by: e.g. 1:80,000 or 1/80,000 e.g. “2 inches to the mile” Ratio or fraction A statement A graphic scale

Chart Scales Small Scale = Large Area e.g. 1/100,000 vs. 1/10,000 Large Scale = Small Area The larger the scale, the greater the detail.

Chart Production National Geospacial-Intelligence Agency (NGA) Charts are produced by the government Formerly National Imagery and Mapping Agency (NIMA) Charts of foreign waters: Lots of other names, too!

Chart Production National Ocean Service (NOS) Part of National Oceanography & Atmospheric Administration (NOAA) Charts of US coastal and inland waters:

Chart Numbers 1 digit – no scale Charts are numbered with 1 to 5 digits. 2 digits – 1:9,000,001 and smaller 3 digits – 1:2,000,001 to 1:9,000,000 (e.g. Chart No. 1) 4 digits – Special Purpose (e.g. Plotting Sheets) 5 digits – 1:2,000,000 and larger

Chart Numbers 1 st digit = Ocean Basin 2 & 3 Digit Charts Cover entire (or most of) ocean basins

Chart Numbers

1 st digit = Coastal Region 5 Digit Charts Most common charts, day-to-day use. (Not the same as Ocean Basin) 1 st & 2 nd digits = Subregion Digits 3-5 = Specific Location (Counterclockwise within subregion)

Regions and Subregions

Chart Numbers

Chart Catalogs Free Produced by NGA and NOS Lists authorized sales agents Several volumes, by location Lists all available charts

Use of the NGA Catalog Step One: Review the index of the world’s coastal regions/subregions. Example: You are planning to enter Rio de Janeiro, Brazil.

Use of the NGA Catalog Rio de Janeiro lies in Region 2

Step #2 Locate the Small-scale Coastal Chart Use of the NGA Catalog

Step #3 Locate the Harbor Charts

Chart Scales Charts are classified by Scale Used for mid-ocean navigation Sailing charts < 1:600,000 General charts 1:150,000 to 1:600,000 Coastwise navigation Outside reefs and shoals

Chart Scales Inshore coastal navigation Coastal charts 1:50,000 to 1:150,000 Harbor charts >1:50,000 Small harbors & anchorages Entering Large bays

Chart Stock Numbers For purchasing and inventory purposes. 26 = subregion E.g. 26AHA A = portfolio number HA = chart series = chart number HA = harbor CO = coastal GN = general WO = world

Chart Ordering Can buy a portfolio Can purchase individual charts (E.g. 26A = General & Harbor charts for 26) You must have the latest, large scale chart for your location. All (or most) charts in a subregion

Chart Ordering Latest version is printed upon order and shipped overnight Print on demand Authorized Chart Agent Copies on hand May need correcting prior to use

Introduction to Navigation Questions?